PULLMAN, Wash. — Schweitzer Engineering Laboratories, Inc. (SEL) today announced three new additions to the popular SEL-787 family of differential protection relays, providing low-cost, versatile transformer differential protection for an expanded range of applications.

The new relays (SEL-787-3E, -3S, -4X) offer the following benefits for transformer protection:

Protection for transformers in 2-, 3-, or 4-terminal applications using one relay family, keeping schematics simple and minimizing the learning curve

Sensitive detection of internal faults near the grounded neutral with as many as three restrictive earth fault (REF) elements

“Customers can now use the SEL-787 to protect transformers in up to four-terminal differential applications and can standardize on a single transformer protection platform to reduce business and operation costs,” said Dave Whitehead, SEL vice president of R&D. “We have also added Spanish language support in the new SEL-787 relays that includes the acSELerator® software, front-panel overlay and relay scripting, allowing Spanish-speaking engineers and technicians to quickly configure and use the relays.”

The additional 4 pushbuttons and 16 tricolor LEDs on the front panel, all of which are programmable, quickly inform operators and support efficient local or remote control. Similar to the existing SEL-787, there are two slots available for additional I/O cards. The IEC 60870-5-103 protocol is also available as an option. The SEL-787-3E, -3S and -4X are available to order today. For more information on features, benefits and applications, visit SEL-787-3E/-3S/-4X.

SEL serves the power industry worldwide through the design, manufacture, supply and support of products and services for power system protection, monitoring, control, automation, communications and metering. For more than 30 years, SEL has provided industry-leading performance in products and services, local technical support, a 10-year worldwide warranty and a commitment to making electric power safer, more reliable and more economical.